Machining down lifter bores, how far?

[subwoofer]

Still a slow moving project...

I have finally made myself a tool I think will enable me to machine down the lifter bores for the hydraulic -> T1 lifter conversion, now one quick question remains: How far? I think I have seen 6mm somewhere, how much is commonly removed?

[Dan Dryden]

If you can machine it yourself, why not just take it down 1mm at a time and keep offering up you cam and lifters to check for clearance?
With the variations between cams and lifters, I don't think there is a definitive "one size fits all" answer to your question.

[Marc]

If you can machine it yourself, why not just take it down 1mm at a time and keep offering up you cam and lifters to check for clearance?
With the variations between cams and lifters, I don't think there is a definitive "one size fits all" answer to your question.

That's the best approach, lobe base circles and lifter "foot" thickness/fillet radii can vary and there's no point in removing any more than needed if you have the cam & lifters that will be used on hand. I don't know what's considered the minimum safe clearance but I like 1mm, that's usually enough to cover small differences from one to another.

[sideshow]

Be aware of the radius under the mushroom head of a t-1 lifter and even the most expensive lifters on the planet will vary there in that radius and head thickness. Same probably goes for whatever you are sleeving the case with.

My method is to treat each lifter/case hole/cam lobe as unique, then decide what lifter goes in what hole, then using the camshaft and “No cam bearing” determine if the boss needs trimming or chamfer based on if the lobe peak touches.

Obviously, I use cam bearing during finial assembly. I recommend not leaving them out.

[Marc]

...Obviously, I use cam bearing during finial assembly. I recommend not leaving them out.

[subwoofer]

What is that rattling sound?

I think I'll try machining like Sideshow suggested, have clearance (just some) from the lobe to the lifter with no bearing and no lifter bushing. Should hopefully be enough.

Cam will be a W110, btw.

[Marc]

The only reason I prefer to machine them all the same with just a little extra clearance is so that I won't have to do it again next time should the lifters need to be replaced. If the prospect of that doesn't bother you, by all means just take off enough for each individual lifter, leaving the maximum possible support remaining. Either way's "right" it's just a difference of philosophy.

[subwoofer]

I don't think I did a very good job of thinking out loud... I wasn't planning on going one by one, it was more a case of using the cam-less-bearing technique to find the amount of material I need to remove and taking the same amount from all of them. I was also thinking that a back clearance of 1mm with the lifter and lobe touching at peak lift should be safe yet not excessive.

[Marc]

[subwoofer]

Converting to T1 solids, that's the whole point of the procedure, making place for the larger diameter lifter surface over the bushed T4 lifter bores.. I may have forgot to mention that it is for a DJ WBX.

[AMBROSIA]

Mine's being done at the moment.
I'm running a Web 86B but will clearance enough for the 86C should it ever be desired.
I've had terrible trouble getting a bush/lifter combo that is in tolerance so carefully check one before pressing the lot in. As the T1 bushes are too oversized for my application I will be using 912's that will be drilled out and reamed to tolerance.
The other thing to consider is the oiling, depending on the design of your lifters.
Mine are tool steel light weight's but have a smaller oiling groove compared to the stock hydro units, so the plan is to open up the bush holes to compensate.

[Marc]

Converting to T1 solids, that's the whole point of the procedure, making place for the larger diameter lifter surface over the bushed T4 lifter bores.. I may have forgot to mention that it is for a DJ WBX.

Oops, never mind....just cleaned my glasses and re-read the original post, I had missed the "->" between "hydraulic" and "T1" ....I think I'll go back and delete those comments since they're totally irrelevant to this thread.

[subwoofer]

Dang. The makeshift tool I made for this didn't work and fell apart rather quickly. I'll have to find someone to cut them down for me, or at least borrow a tool.

[AMBROSIA]

http://www.geneberg.com/product_info.ph ... 4b785d984.

[buildabiggerboxer]

Rocky sells the lifter bore decking tool, press in the bushes and and then cut. There is no set cutting depth but the minimum is 1mm Clearance OTN of your desired cam.